The technical problem that is successfully solved by the present construction of a versatile mill is to achieve such constructional solutions on the device that will eliminate the deficiencies of known implementations, especially as regards simple transportation, rapid and simple exchange of knives and successful cooling of the milling compartment, so that a continuous working process as well as all kinds of operations will be made possible.
Milling devices that operate according to various principles have been in use. Since the present application describes a versatile mill operating according to the principle of material processing by means of grinding, chopping, or cutting--depending on the type of the rotating knives used--our description will be restricted to this type of devices.
Versions of mills with rotating knives are known which have the knives positioned one above the other on a vertical and profiled shaft, and the mutual position of the knives as well as the distance between them can be adjusted according to the type of processing. Such is, for example, the basic design of a mill described in the Yugoslav patent documents no. 26030 and 30648. In this design each knife is fitted with a centrically made rectangular opening intended for positioning individual knives between themselves, this opening having the same dimensions as the shaft. In this way individual knives can be shifted aside by an angle of 90.degree.. The positioning of other angles between the knives can be realized by a multi-angular shaft with the knives having the corresponding openings, or by knives which are expressly fitted with openings shifted by a certain angle in order to be pushed onto the shaft. A drawback of such positioning is that at a sudden stop of the knife, e.g. due to a foreign object in the material to be milled, both the knife and the shaft may get damaged, and it will be hard or even impossible to remove a knife thus damaged from the shaft. Another drawback lies in the fact that individual knives are predetermined for a definite position, which considerably limits the possibilities of combination.
Because of the installation of the driving motor under the milling compartment, the milling part and thereby the milled material receive excessive heating. Particularly in an enclosed milling system, when operating for a longer time, the mill gets overheated. Therefore, it has to be stopped from time to time, also because the milled substance overheats. In addition, when the driving motor is installed under the bottom of the milling compartment, the driving motor shaft usually extends into the milling compartment. This may cause, due to the unfavourable length of the entire shaft, constructional difficulties and make it difficult to transport the mill because of its height.